ON THE STOCKDALE SHALES. 713 



with that of similar beds is more difficult, but fully confirms the 

 conclusions come to after examining the Graptoliteis. 



The different forms of Phyllocarida might have been considered 

 along with the Graptolites, as they occur in Graptolitic rocks. 



Of these Discinocaris is found in the Birkhill Shales and their 

 Bohemian equivalents ; whilst Peltocaris aptycJioides and Aptychopsis 

 Lapivortlii are also found in the Birkhill Shales. 



Of the other fossils, Encrinurus punctatus, Calymene Bliimenhachii, 

 and Leptcma quinquecostata are found both in Llandovery Beds and 

 in beds above and below them, whilst Favosites mullochensis occurs 

 in the Llandovery Beds of the Girvan area. 



Phacops elegans has been recognized in the Mulloch-Hill Sand- 

 stones (a specimen from this locality being preserved in the "Wood- 

 wardian Museum) and in the corresponding beds at the Gasworks, 

 Haverfordwest. It also occurs in the Gala Beds of Devil's Bridge, 

 Aberystwith, where it was found some years ago by one of the 

 authors. 



In IS'orway it is common in the sandstones of stage 5/3 of Kjerulf, 

 which correspond in lithological characters and fossil contents with 

 the Mulloch-Hill Beds and the beds at the Gasworks, Haverford- 

 west. Dr. Schmidt records it from the Eaikiill Beds of Eussia, 

 where it is found along with other fossils occurring in Ejerulf's 5/3, 

 and DipJograptus esthonus *. All these beds are admitted to be of 

 Llandovery age, with the exception of the Devil's-Bridge deposit, 

 which is compared with the Gala Group, and therefore indirectly 

 with the Tarannon Shales. That some of the Trilobites occurring in 

 our Skelgill Beds do pass up into the Browgill Beds seems clear from 

 the occurrence of many of them in the calcareous band immediately 

 below the Coniston Flags in Austwick Beck, and we have one speci- 

 men of Phacops elegans var. glaher from the Browgill Beds of Brow- 

 gill, though its exact position was not ascertained. More Trilobites 

 would probably be found in the Browgill Beds of the central area if 

 the calcareous bands were further examined ; for the carbonate of lime 

 of these beds was probably derived from Trilobites, as in the case of 

 the Trilobitic mudstones of the Skelgill group. 



The examination of the occurrence of Phacops elegans shows that 

 it is a Llandovery-Tarannon form, and it has not been recorded from 

 earlier or later formations. 



Phacops mucronatus, Brongn., occurs in the Llandovery Beds of 

 Haverfordwest, and in the Upper Brachiopod Schists of Westrogothia. 

 It is different from the form which occurs in the Ashgill Shales, and 

 which seems to correspond with the form from the Lower Brachiopod 

 Schists. 



Orthoceras araoieosum, Barr., is found in the Wenlock and Ludlow 

 rocks of Britain, and in the beds of Barrande's Stage E, in 

 Bohemia f. 



The other fossils are new. Of these, Ampyx aloniensis belongs to 



* Schmidt, 'Eevision der ostbaltischen silurischen Trilobiten,' p. 43; and 

 Q. J. a. S. vol. xxxviii. p. 526. 



t Blake, * British Fossil Cephalopoda,' p. 124. 



